Map data having unequal interval

ABSTRACT

A map is stored in a robot that has a travelling unit, wherein the map is represented by a grid having a plurality of parcels, and a data set is assigned to each parcel such that the grid is represented by a plurality of data sets, each data set assigned to each parcel includes a characteristic value representing a characteristic of the parcel, and a grid value representing a shape of the parcel.

BACKGROUND OF THE DISCLOSURE Technical Field

The disclosure relates to map data, and more specifically relates to mapdata having an unequal interval.

Related Art

Conventionally, an autonomous work vehicle stores map data of a workarea. As the work area increases, a data size of the map data alsoincreases such that handling of the data becomes difficult. For example,in some cases, 90% of an entire control software of the autonomous workvehicle may be map data.

Therefore, a way for decreasing the data size of the map data is needed.When the data size of the map data is decreased, then the hardwarespecification required for the autonomous work vehicle may be lowered.

SUMMARY

According to an embodiment of the disclosure, a map is stored in a robotthat has a travelling unit, wherein the map is represented by a gridhaving a plurality of parcels, and a data set is assigned to each parcelsuch that the grid is represented by a plurality of data sets, each dataset assigned to each parcel includes a characteristic value representinga characteristic of the parcel, and a grid value representing a shape ofthe parcel.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, withreference to the accompanying drawings which are meant to be exemplary,not limiting, and wherein like elements are numbered alike in severalFigures.

FIG. 1 is a schematic diagram illustrating a conventional representationof map data;

FIG. 2 illustrates an example of the information that is assigned to thecharacteristic values;

FIG. 3 illustrates a conversion of map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure;

FIG. 4 shows a column number and row number assigned to the mapaccording to a conventional representation, compared to a vertex numberrepresentation assigned to the map according to an embodiment of thedisclosure;

FIG. 5 shows a map data representation according to an embodiment of thedisclosure.

FIG. 6 illustrates STEP 1 of converting map from a conventionalrepresentation to a representation according to an embodiment of thedisclosure;

FIG. 7 illustrates STEP 2 of converting map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure;

FIG. 8 illustrates the conversion at the end of STEP 2;

FIG. 9 illustrates STEP 3 of converting map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure;

FIG. 10 illustrates the conversion at the end of STEP 3;

FIG. 11 is a schematic diagram illustrating the map data of FIG. 1 usinga representation of map data according to an embodiment of thedisclosure.

FIG. 12A and FIG. 12B illustrate a flow chart of converting map datafrom a conventional representation to a representation according to anembodiment of the disclosure;

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a schematic diagram illustrating a conventional representationof map data. Referring to FIG. 1 , a map M1 is represented by a gridhaving a plurality of parcels P. The map M1 has rows 1~18 and columns1~27, and has a total of 486 parcels P. The parcels P correspond to thecells of the grid. The number of rows, columns and parcels are as oneembodiment only and the disclosure is not limited hereto. The number ofrows, columns and parcels may be set according to requirements.

It should be noted, in the conventional representation of map M1 shownin FIG. 1 , all of the plurality of parcels P are divided intoequivalent row intervals and equivalent column intervals. The rowinterval and column interval may be, for example, 0.1 meter, 0.5 meters1.5 meter, 2.0 meters, and the like and is not intended to limit thedisclosure. In the map M1 shown in FIG. 1 , the row interval and thecolumn interval are the same, however in another embodiment of thedisclosure, the row interval may differ from the column interval.

The map M1 may be stored in a processor or a memory of a robot. Therobot may have a travelling unit. In addition, the robot may be a workmachine having a working unit. The travelling unit may be, for example,a motor, an engine, a wheel, a propulsion system and/or the like whichallows the robot to travel. The motor and/or engine may be powered bygas or battery and the like and is not intended to limit the disclosure.The work unit may be, for example, a blade for cutting grass or a plowfor plowing snow, however the work unit of the disclosure is not limitedthereto.

Each parcel P is assigned a characteristic value CV which represents acharacteristic of the parcel P. For example, information relating to atravelability of an area represented by the parcel P is assigned to thecharacteristic value CV of each parcel P. In another example,information relating to a control of a working unit (blade, plow, etc.)of the robot at an area represented by the parcel P is assigned to thecharacteristic value CV of each parcel P.

FIG. 2 illustrates an example of the information that is assigned to thecharacteristic values. Referring to FIG. 2 , the characteristic value CV=0, for example, may represent a work area of the robot; thecharacteristic value CV =1, for example, may represent Non-work area ofthe robot; the characteristic value CV =2, for example, may represent anobstacle such as a tree or a rock or the like; the characteristic valueCV =3, for example, may represent an area wire delineating a boundary ofthe work area; the characteristic value CV =4, for example, mayrepresent a power charging station of the robot; the characteristicvalue CV =5-9, for example, may represent a boundary type such as a “donot cross boundary”, a “crossable boundary”, a “u-turn prior toboundary” and the like.

The above described information that are assigned to the characteristicvalues CV are examples only, and are not intended to limit thedisclosure. Other information may be assigned to the characteristicvalues CV according to requirements. For example, the informationassigned to a characteristic value may include information regarding awatering station for a plant watering robot. Furthermore, somecharacteristic values CV 1~9 were described in the example shown in FIG.2 , however the disclosure is not limited thereto and other numbers, forexample, 13, 25, 77, 103 may be used for the characteristic values CVaccording to requirements. In addition, although nine characteristicvalues CV (1~9) were described in the example shown in FIG. 2 , morethan nine or less than nine characteristic values CV may be assigned ascharacteristic values CV according to requirements.

FIG. 3 illustrates a conversion of map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure. Referring to FIG. 3 , a map M2 and a map M3 are maps of asame area but with differing representation. The map M2 shown on theleft is represented according to the conventional method. The map M3shown on the right is represented according to an embodiment of thedisclosure. The map M2 has 3 columns and 3 rows. A map area of the mapM2 and a map area of the map M3 are the same. For example, assuming, forexample, the row interval is 1.0 meters and the column interval is 1.0meters, the map area of the map M2 and the map area of the map M3 bothrepresent a map area of 3.0 meters x 3.0 meters. In the conventionalrepresentation of the map M2, all of the plurality of parcels P aredivided into equivalent row intervals and equivalent column intervals.In this way, the conventional representation of the map M2 requires atotal of nine parcels P to represent the map M2.

Referring to FIG. 3 , in the representation of map M3 according to anembodiment of the disclosure, each of the parcels P are not all dividedinto equivalent row intervals and equivalent column intervals. In otherwords, the row intervals and column intervals of the plurality ofparcels P are different from each other, and are not all the same suchas in the map M2. Accordingly, the conventional representation of themap data M2 required a total of nine parcels P to represent the map M2,however the representation of the map M3 according to an embodiment ofthe disclosure requires less than nine parcels P to represent the mapM3. The map M3 in FIG. 3 is represented by a total of three parcels P.The map M2 and the map M3 are maps of the same area but with differingrepresentation.

Next, a conventional representation of map data will be explained.

FIG. 4 shows a column number and row number assigned to the mapaccording to a conventional representation, compared to a vertex numberrepresentation assigned to the map according to an embodiment of thedisclosure. Referring to FIG. 4 , the map M2 has 3 rows and 3 columns,and has 9 parcels P. Each parcel P is assigned a row number and a columnnumber. A characteristic value CV is assigned to each parcel P. Thecharacteristic values CV assigned to each parcel P is an example only,and the disclosure is not limited hereto. The characteristic values CVmay be assigned according to requirements.

Referring to FIG. 4 , in the map M2, all of the plurality of parcels Pare divided into equivalent row intervals. Furthermore, in the map M2,all of the plurality of parcels P are divided into equivalent columnintervals. In the map M2, the row interval and the column interval arethe same, however in another embodiment of the disclosure, the rowinterval may differ from the column interval. By knowing the totalnumber of columns and the total number of rows in the map M2, a map dataMAP_data_M2 of the map M2 may be represented by listing thecharacteristic value CV of each parcel P in order. Here, thecharacteristic value CV of each parcel P is listed in order withpriority given to the column number such that map data MAP_data_M2 = {2,2, 2, 2, 1, 1, 2, 1, 1}. When priority is given to the column number,the map data MAP_data_M2 = {2, 2, 2, 2, 1, 1, 2, 1, 1}. In the presentembodiment of FIG. 4 , the representation of the map data when priorityis given to the column number is the same representation as whenpriority is given to the row number. Whether priority is given to thecolumn number or the row number is not intended to limit the disclosure,and may be set according to requirements.

It should be noted, a prerequisite to the conventional method ofrepresenting the Map data MAP_data_M2 by listing only the characteristicvalue CV of each parcel P in order is that all of the plurality ofparcels P of the map M2 are of the same size, since the area size ofeach parcel P is not listed in the map data representation. In otherwords, the prerequisite to the conventional method of representing mapdata MAP_data_M2 is that each of the parcels P is divided into theequivalent row interval and the equivalent column interval.

A deficiency in representing the map data MAP_data_M2 according to theconventional method (by listing only the characteristic value CV of eachparcel P in order of row number or column number) is that when thenumber of columns and the number of rows are doubled, the number ofparcels P are quadrupled, which causes the number parcels P for a largermap (or a map having small interval) to become large. For example, formap M2 that has 3 rows and 3 columns, then 9 parcels P are needed torepresent nine characteristic values CV. However, for a map that has,for example, 6 rows and 6 columns, then 36 parcels P are needed forrepresenting thirty-six characteristic values CV.

When trying to fit the map data that has 6 rows and 6 columns into thesame data size as map data that has 3 rows and 3 columns, then the gridinterval must be increased (roughened). For example, if the map has arow interval of 1.0 meters and a column interval of 1.0 meters, then themap that has 3 rows and 3 columns may represent a map area of 3.0 metersx 3.0 meters. In comparison, when the map is created for representing amap area of 6.0 meters x 6.0 meters, the number of parcels P isquadrupled from 9 parcels P to 36 parcels P, assuming that the rowinterval and column interval are both maintained at 1.0 meters. In orderto fit the map data representing a 6.0 × 6.0 meter area into the samedata size of map data that representing a 3.0 x 3.0 meter area, the rowinterval may be increased to 2.0 meters and the column interval may beincreased to 2.0 meters. In this way, by increasing the row interval to2.0 meters and the column interval to 2.0 meters, the map that has a 6.0× 6.0 meter area may be represented by 9 parcels P, which is the samenumber of parcels P as the map that has a 3.0 × 3.0 meter area. However,when the grid interval (row interval and/or column interval) isincreased to 2.0 meters, the resolution of the map is decreased.

Next, a map data representation according to an embodiment of thedisclosure will be explained.

Referring to FIG. 4 , the map M3 has 3 rows and 3 columns representing amap area of 3.0 meters x 3.0 meters. The map M3 has three parcels P. Avertex ①~③ is assigned to each of the three parcel P. A map dataMAP_data_M3 according to an embodiment of the disclosure is representedby a plurality of data sets representing the vertexes ①~③. In moredetail, the map M3 is represented according to an embodiment of thedisclosure by the map data MAP_data_M3 = {1, 1, 4, 2, 2, 1, 2, 2, 4, 2,2, 2, 4, 4, 1}. The first five numbers corresponds to a data set①, whichis the data set representing the vertex①. The sixth to tenth numberscorresponds to a data set②, which is the data set representing thevertex②. The eleventh to fifteenth numbers corresponds to a data set③,which is the data set representing the vertex③.

That is to say, data set① =(1, 1, 4, 2, 2); data set② = (1, 2, 2, 4, 2);data set③ = (2, 2, 4, 4, 1). Consequently, the map data is representedby map data M3 = { data set①, data set ②, data set③}.

Each data set①~③ assigned to each parcel P includes a grid value GVrepresenting a shape of the parcel P, and a characteristic value CVrepresenting a characteristic of the parcel P. The grid value GV in eachdata set of each parcel is assigned two vertex values to represent theshape of the parcel. That is to say, the grid value GV includes a firstvertex value detailing the row number and the column number of a topleft vertex of the parcel P, and a second vertex value detailing the rownumber and the column number of a bottom right vertex of the parcel P.In another embodiment of the disclosure, the first vertex value mayinclude the information detailing the row number and the column numberof top right vertex of the parcel P, and the second vertex valuedetailing the information about the row number and the column number ofbottom left vertex of the parcel P. The specific representations of thefirst vertex value and the second vertex value may be set according torequirements.

Since not all of the plurality of parcels P of the Map M3 are of thesame size, the first vertex value and the second vertex value includedin the grid value GV identifies the shape of the parcel P. Furthermore,a size of the parcel P may be derived by calculation using the firstvertex value and the second vertex value. In more detail, the first twovalues in the data set① =(1, 1, 4, 2, 2) make up the column number androw number of the first vertex value. The third and fourth number in thedata set① =(1, 1, 4, 2, 2) make up the column number and row number ofthe second vertex value. Therefore, a size of the parcel P may becalculated using a difference between the column numbers and adifference between the row numbers of the first vertex value and thesecond vertex value. The fifth number in the data set① =(1, 1, 4, 2, 2)make up the characteristic value CV of the parcel P.

In other words, each of the data sets ①~③ are made up by five values.The five values representing each data set ①~③ are {column number ofvertex, row number of vertex, column number of vertex located atadjacent right, row number of vertex located at adjacent bottom,characteristic value CV}. The five values {column number of vertex, rownumber of vertex, column number of vertex located at adjacent right, rownumber of vertex located at adjacent bottom, characteristic value CV}make up a data set, and the data set is assigned to each parcel P suchthat the map M3 is represented by a plurality of data sets①~③.

FIG. 5 shows a map data representation according to an embodiment of thedisclosure. Referring to FIG. 5 , a map M4 has 100 columns and 100 rows.Assuming the row interval is 1.0 meters and the column interval is 1.0meters, the map area of the map M4 represent a map area of 100 meters x100 meters. That is to say, a map area of the map M4 is larger than amap area of the map M2 and map M3, since the map M2 and map M3 representa map area of 3 meters x 3 meters. However, the map M4 according to anembodiment of the disclosure is represented by a total of three parcelsP, while the map M3 is also represented by a total of three parcels P,while the map M2 is represented by a total of nine parcels P. Aconventional representation of the map M4 having 100 columns and 100rows would require a total of 10, 000 parcels to represent the map.Therefore, in the map M4 representation according to an embodiment ofthe disclosure, the data size of the map M4 may be reduced since onlythree parcels P are needed to represent the map M4. When the data sizeof the map is decreased, then the hardware specification required forthe autonomous work vehicle may be lowered.

Next, a method of converting the conventional representation to arepresentation according to an embodiment of the disclosure will beexplained.

FIG. 6 illustrates STEP 1 of converting map from a conventionalrepresentation to a representation according to an embodiment of thedisclosure. Referring to FIG. 6 , a column number and a row number arenot assigned to each parcel P, but rather the column number and the rownumber are assigned to the border line (cell line) between adjacentparcels P. Accordingly, in the vertex representation according to thepresent embodiment, there will be one additional row number and oneadditional column number compared to the representation by theconventional method. Next, the conventional representation of map datais converted to a vertex representation by assigning the vertexes ①~⑨ toeach parcel P. It should be noted, the conventional representation ofmap data is converted to a vertex representation while maintaining theequal column interval and equal row interval.

Referring to FIG. 6 , a first vertex ① is assigned to the vertex wherethe column 1 and row 1 converges; a second vertex ② is assigned to thevertex where the column 2 and row 1 converges; a third vertex ③ isassigned to the vertex where the column 3 and row 1 converges; a fourthvertex ④ is assigned to the vertex where the column 1 and row 2converges; a fifth vertex ⑤ is assigned to the vertex where the column 2and row 2 converges; a sixth vertex ⑥ is assigned to the vertex wherethe column 3 and row 2 converges; a seventh vertex ⑦ is assigned to thevertex where the column 1 and row 3 converges; an eight vertex ⑧ isassigned to the vertex where the column 2 and row 3 converges; a ninthvertex ⑨ is assigned to the vertex where the column 3 and row 3converges.

Referring to FIG. 6 , a data set (data sets ①~⑨) is assigned to eachparcel P. Each data set①~⑨ assigned to each parcel P includes a gridvalue GV representing a shape of the parcel P, and a characteristicvalue CV representing a characteristic of the parcel P. That is to say,each data set①~⑨ is assigned five values including {column number ofvertex, row number of vertex, column number of vertex located atadjacent right, row number of vertex located at adjacent bottom,characteristic value CV} to make up each data set.

According to the map data representation of the disclosure, the datasets ①~⑨ shown in FIG. 6 may be represented as below:

Example of data set ①~⑨ shown in FIG. 6

-   data set ① = {1, 1, 2, 2, 2}, data set ② = {2, 1, 3, 2, 2}, data set    ③ = {3, 1, 4, 2, 2}-   data set ④ = {1, 2, 2, 3, 2}, data set ⑤ = {2, 2, 3, 3, 1}, data set    ⑥ = {3, 2, 4, 3, 1}-   data set ⑦ = {1, 3, 2, 4, 2}, data set ⑧ = {2, 3, 3, 4, 1}, data set    ⑨ = {3, 3, 4, 4, 1}

In this way, the map data M3 may be represented as map data M3 = {dataset ①, data set ②, data set ③, data set ④, data set ⑤, data set ⑥, dataset ⑦, data set ⑧, data set ⑨}.

In the present disclosure, each parcel P is a rectangular shape.Furthermore, the grid value in each data set of each parcel is assignedtwo vertex values to represent the shape of the parcel P.

FIG. 7 illustrates STEP 2 of converting map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure. In STEP 2, parcels among the plurality of parcels that aredivided into equivalent column intervals are obtained, and when thecharacteristic values of two adjacent parcels having equivalent columnintervals are equal to each other, the two adjacent parcels areintegrated into one parcel and the grid value of the one parcel isupdated.

Specifically, referring to FIG. 7 , parcels P in adjacent columns havingthe same row interval, and having the same characteristic value CVconsecutively repeated are deleted. Referring FIG. 7 , the vertex①,vertex② and vertex③ all have characteristic values CV of “2”consecutively repeated. Accordingly, the vertex② and the vertex③ areboth deleted, and consequently the data set② and data set③ are deleted.

After deleting the data set① and data set③, then the data set① isupdated from data set ① = {1, 1, 2, 2, 2} into data set ① = {1, 1, 4, 2,2}. That is to say, the column number of the second vertex value isupdated from “2” to “4”. This process is performed for each row of themap data.

FIG. 8 illustrates the conversion at the end of STEP 2. At the end ofSTEP 2, the vertex②, vertex③, vertex⑥, vertex⑨ are deleted, andconsequently the data set②, data set③, data set⑥, data set⑨ are deleted.The data set①, data set④, data set⑤, data set⑦, data set⑧ remain. Then,the data set①, data set④, data set⑤, data set⑦, data set⑧ are updated asbelow:

-   data set① = {1, 1, 4, 2, 2}-   data set④ = {1, 2, 2, 3, 2}, data set⑤ = {2, 2, 4, 3, 1}-   data set⑦ = {1, 3, 2, 4, 2}, data set⑧ = {2, 3, 4, 4, 1}

FIG. 9 illustrates STEP 3 of converting map data from a conventionalrepresentation to a representation according to an embodiment of thedisclosure. In STEP 3, parcels among the plurality of parcels that aredivided into equivalent row intervals are obtained, and when thecharacteristic values of two adjacent parcels having equivalent rowintervals are equal to each other, the two adjacent parcels areintegrated into one parcel and the grid value of the one parcel isupdated. That is to say, parcels P in adjacent rows having the samecolumn interval, and having the same characteristic value CVconsecutively repeated are deleted.

Referring to FIG. 9 , the parcels P in row 1 and row 2 have differentparcel sizes, therefore vertex④ and vertex⑤ cannot be deleted. Regardingrow 3, since vertex⑦ has a same column interval as vertex④, and bothhave the same characteristic value CV of “2”, then vertex⑦ is deleted.Similarly, since vertex⑧ has a same column interval as vertex⑤, and bothhave the same characteristic value CV of “1”, then vertex⑧ is deleted.

FIG. 10 illustrates the conversion at the end of STEP 3. At the end ofSTEP 3, the vertex⑦, vertex⑧ are deleted, and consequently the dataset⑦, data set⑧ are deleted. The data set①, data set④, data set⑤ remainin the map data. Then, the data set①, data set④, data set⑤ are updatedas below:

-   data set① = {1, 1, 4, 2, 2}-   data set④ = {1, 2, 2, 4, 2}, data set⑤ = {2, 2, 4, 4, 1}

The map data M3 is now represented by map data M3 = {1, 1, 4, 2, 2, 1,2, 2, 4, 2, 2, 2, 4, 4, 1}. Consequently, the map data is represented bymap data M3 = { data set①, data set ④, data set⑤}. Alternatively, thedata set④ and data set⑤ may be re-numbered as data set② and data set③according to requirements, such that the map data may be represented bymap data M3 = { data set①, data set②, data set③}.

In STEP 2 illustrated in FIG. 7 , when the characteristic values of twoadjacent parcels having equivalent “COLUMN” intervals are equal to eachother, the two adjacent parcels are integrated into one parcel and thegrid value of the one parcel is updated. In STEP 3 illustrated in FIG. 9, when the characteristic values of two adjacent parcels havingequivalent “ROW” intervals are equal to each other, the two adjacentparcels are integrated into one parcel and the grid value of the oneparcel is updated. Although in the present explanation, STEP 2 wasperformed before STEP 3, however the disclosure is not limited thereto.In another embodiment of the disclosure, STEP 3 may be performed beforeSTEP 2. In addition, in another embodiment of the disclosure, only oneof STEP 2 or STEP 3 may be performed. Accordingly, STEP 2 illustrated inFIG. 7 , and STEP 3 illustrated in FIG. 9 both show when parcels amongthe plurality of parcels that are divided into equivalent intervals areobtained, and when the characteristic values of two adjacent parcelshaving equivalent intervals are equal to each other, the two adjacentparcels are integrated into one parcel and the grid value of the oneparcel is updated.

FIG. 11 is a schematic diagram illustrating the map data of FIG. 1 usinga representation of map data according to an embodiment of thedisclosure. It should be noted, in the representation of map dataaccording to the present disclosure, the row interval and columninterval of the plurality of parcels P may be different from each other.In more detail, the grid interval (row interval and/or column interval)is increased at a particular area where the same characteristic valuesCV are consecutively repeated.

Referring to FIG. 11 , the grid interval is increased at a plurality ofparticular areas where the characteristic value CV of 0 is consecutivelyrepeated. By increasing the grid interval at a particular area where thesame characteristic values CV are consecutively repeated, a data size ofthe map data may be reduced.

Comparing to FIG. 1 , in the map data M in which all parcels P haveequivalent intervals, the conventional method of representing map data Mbecomes wasteful because a characteristic value CV of 0 is required tobe kept for each parcel P, even in a case when the characteristic valueCV of 0 is consecutively repeated.

In the example embodiment of FIG. 11 , the characteristic values CV of“5”, “7”, “9” which represent a predetermined boundary type arerepresented by a relatively finer grid interval compared to some of thegrid intervals of the characteristic values CV of “0” which representthe work area. Similarly, the characteristic values CV of “1” whichrepresent a non-work area are represented by a relatively finer gridinterval compared to some of the grid intervals of the characteristicvalues CV of “0” which represent the work area. In the representation ofmap data according to the example embodiment of FIG. 11 , the gridresolution may be maintained at a higher resolution near or around theborders, and the resolution may be decreased (i.e. increased gridinterval) at non-border areas and areas where there are fewer or noobstacles. The resolution at each particular area such as the borders orareas where there are fewer or no obstacles may be set according torequirements and is not intended to limit the disclosure.

It should be noted, the configuration of FIG. 11 is an exampleconfiguration only, and the disclosure is not limited thereto. Inanother embodiment of the disclosure, some grid intervals of thecharacteristic values CV of “0”, “1”, “5”, “7”, “9” repeatedconsecutively near or at the border may also be represented by anincreased grid interval according to requirements.

FIG. 11A and FIG. 11B illustrates a flow chart of converting map datafrom a conventional representation to a representation according to anembodiment of the disclosure. Referring to FIG. 11A, in step S20, createa map using the conventional method. Next, in step S30, convert the mapdata to vertex representation. In step S40, initialize the currentvertex number to vertex①.

In step S50, compare is the current vertex number greater than or equalto the total number of vertexes. If “no”, proceed to step S60.

In step S60, compare is the current vertex cell value the same as in theadjacent right vertex. If “yes”, proceed to step S70.

In step S70, search the vertexes to the right and DELETE the vertexeswhich have the same cell value as the current vertex. When a vertexhaving a different cell value than the current Cell is found, end thedeletion processing and update the current vertex data.

After the completion of step S70, proceed to step S90 and change thecurrent vertex to that of the last deleted vertex number +1. After thecompletion of step S90, repeat step S50.

If the answer to step S60 is “no”, proceed to step S80. In step S80, add+1 to the current vertex number. After the completion of step S90,repeat step S50.

If the answer to step S50 is “yes”, proceed to step S200 of FIG. 11B.

In step S200, initialize the current column number to 1, and the rownumber to 1.

In step S210, check have all vertices been considered for target ofdeletion. If “no”, proceed to step S220.

In step S220, check has the vertex of the current column and row numberbeen deleted. If “yes”, proceed to step S250.

If the answer to step 220 is “no”, proceed to step S230. In step S230,check is the cell value and cell size of the current vertex the same asin the vertex below. If “no”, proceed to step S250. If “yes”, proceed tostep S240.

In step S240, search vertexes below the current vertex and DELETE thevertexes which have the same cell value and same cell size as thecurrent vertex. When a vertex having a different cell value or cell sizethan the current Cell is found, end the deletion processing and updatethe current vertex data.

After the completion of step S240, proceed to step S250.

In step S250, add +1 to the current column number. After the completionof step S250, proceed to step S260.

In step S260, check is the current column number the right most column.If “no”, repeat step S210. If the answer to step S260 is “yes”, proceedto step S270 and change the current column number to 1, and add +1 tothe current row number. After the completion of step S270, repeat stepS210.

If the answer to step S210 is “yes”, then map data conversion iscompleted.

Although embodiments of the map data according to the disclosure havebeen described above based on some examples, the disclosure is notlimited thereto.

The map having the map representation according to an embodiment of thedisclosure may be created, for example, prior to work being performed bythe robot or during setup of the robot. Furthermore, regional area dataregistered by a user or a dealer may be transmitted to a server and/orthe robot, and the map data reduced by a processor or the like.

The robot may detect a position of the robot, for example, via a GPSreceiver mounted to the robot. The robot may determine whether a currentposition of the robot is inside a particular cell or parcel based on theGPS information of the robot and the vertex values in the map havingunequal row intervals and/or column intervals.

In general, a minimum row interval and a minimum column interval may be,for example, approximately 10 centimetres. However, the row interval andcolumn interval may be made as fine as is necessary for control of therobot, or as fine as the memory storage of the robot allows.

The shape of the parcel P which may be represented by the two vertexvalues is a rectangle. The details of other shapes such as a triangle orpolygon cannot be represented by the two vertex values. Accordingly, therectangle allows for the most reduction in data size.

When the map is to be updated in a case such as when a location ofobstacles change, information detected by the robot or data relating tothe work load of the work unit of the robot may be uploaded, forexample, to a server where the regional area data is updated anddownloaded to the robot.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodimentswithout departing from the scope or spirit of the disclosure. In view ofthe foregoing, it is intended that the disclosure covers modificationsand variations provided that they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. A map stored in a robot that has a travellingunit, wherein the map is represented by a grid having a plurality ofparcels, and a data set is assigned to each parcel such that the grid isrepresented by a plurality of data sets, each data set assigned to eachparcel includes: a characteristic value representing a characteristic ofthe parcel, and a grid value representing a shape of the parcel.
 2. Themap stored in the robot according to claim 1, wherein each parcel is arectangular shape, and the grid value in each data set of each parcel isassigned two vertex values to represent the shape of the parcel.
 3. Themap stored in the robot according to claim 1, wherein parcels among theplurality of parcels that are divided into equivalent intervals areobtained, and when the characteristic values of two adjacent parcelshaving equivalent intervals are equal to each other, the two adjacentparcels are integrated into one parcel and the grid value of the oneparcel is updated.
 4. The map stored in the robot according to claim 1,wherein the map is stored in a processor of the robot, and informationrelating to a travelability of the parcel is assigned to thecharacteristic value of each parcel.
 5. The map stored in the robotaccording to claim 1, wherein the map is stored in a processor of therobot, the robot is a work machine having a working unit, andinformation relating to a control of the working unit is assigned to thecharacteristic value of each parcel.